In the field of battery cells, the volume change generated as the battery charges or discharges is a known yet undesirable side effect, said effect being mentioned in the prior art. For example, US Patent Application 20040115530 describes a method of preventing the detrimental effects of the volume change of the active material in a lead-acid battery cell. In a co-pending patent application IL169,807 by some of the same inventors of this application, herein incorporated by reference, the concept of making use of such so-called “undesirable” volume changes in order to drive a drug-delivery device is described. However, said co-pending application exploits a relatively small volume change (of the order of 10%) as known from traditional battery chemistries, and thus requires a hydraulic or other coupling mechanism in order to exploit the relatively small volume change in an effective manner.
Accordingly, the achievement of a novel battery cell capable of a significant volume change (that is one capable of effectively driving a drug delivery device and herein referred to as a “displacement-generating battery”) allows for a unique, beneficial, simpler and therefore more inexpensive solution for drug-delivery devices to be attained. Notably, such a drug-delivery device, in its simplest embodiment, would not require any mechanical or hydraulic amplification and thus would represent an advance in the art, as it would enable direct displacement of a drug in a reservoir within said drug-delivery device by said battery cell. In addition, since the displacement generated by said battery is directly related to the accumulated electric discharge in the battery, the extent of the displacement of a drug in a reservoir can be very accurately controlled.
It is therefore the object of the present invention to provide a drug-delivery device driven by such a displacement-generating battery.
It is still further object of the present invention to provide a drug-delivery device whose delivery rate and volume of drug delivered is accurately controlled by an electrochemical reaction, and specifically, by an electrochemical reaction that causes a volume change that actuates the delivery of the drug.
It is still further object of the present invention to provide a displacement-generating battery that is used as an actuator which transmits a displacement resulting from an electrochemical reaction via a coupling component in such a manner that a drug contained within a drug reservoir affected by the coupling is forced through an administration means into the body of a patient.
It is a further object of the invention that said drug-delivery be relatively insensitive to temperature and ambient pressure changes.
It is a still further object of this invention to provide a drug-delivery device with a minimum of moving parts.
It is a still further object of this invention to provide a drug-delivery device where the displacement of the drug chamber can be inherently determined from the state of discharge of the battery.
It is a still further object of this invention to provide a drug-delivery device which does not suffer from a lag in response time.
It is a still further object of this invention to provide a drug-delivery device which is inherently waterproof.
It is still further object of the present invention to provide a drug-delivery device where control and maintenance issues are simpler than in existing approaches and with less potential failure modes.
It is still further object of the present invention to provide a drug-delivery device in which the displacement-generating battery also provides the power to operate the electronics of the device thus advantageously obviating the need for having a further battery cell to power the electronics of the drug-delivery device and so the device is simplified, made more efficient, and lowered in cost.
These and other objects of this invention will become more evident in the summary of the invention and in the description of the preferred embodiment.